In large PV arrays there is a problem detecting ground faults and potential ground faults. Every solar PV module contributes some leakage to its frame or mounting structure. In a conventional system all these leakage currents sum into a current which may flow through a fused connection to protective earth or ground. This fuse is often located in a downstream inverter. With large numbers of modules the “normal leakage current” can often be in the range of amperes. This can mask individual issues which may create safety or reliability issues. In addition to normal leakage current, another potential problem may exist when there is a small unintended gap between conductors. For example, a pinched wire may only have a small gap between a PV rail and ground. This gap may not arc over during normal operation but it is a potential hazard. If there are unanticipated voltage changes in this rail voltage this gap may arc over. There is a well documented fire at a Target® store where some of these hazards might have contributed to the fire.